Analyses were run in PRSice using PRS as a continuous measure. We tested associations between PRS, symptoms and cognitive variables using linear regression models. We tested two models for symptom variables: (1) the first model controlled for the effects of base covariates (age, sex and ancestry using four multidimensional scaling components). (2) Due to statistically significant correlations observed between neurocognitive variables and symptom dimensions, we also tested a second model adjusting for neurocognition in addition to base covariates. For cognitive variables, we tested one model controlling for the effects of base covariates. Results are presented as change in variance (R2 of model minus R2 of the reduced covariates only model) and overall significance of the model. We report both unadjusted p-values as well as permutation based p-values addressing multiple comparisons issue to identify best fit PRS.
